14 April 2010

My compost hot water system

This all stems from a Frenchman named Jean Pain. I discovered Jean Pain's composting method back in 2008 while browsing for info on composting toilet systems. All that existed then was a single article in the Readers Digest from 1982. So I started a Wikipedia article, defended the notability challenges, negotiated copyrights for images of Jean Pain, and watched it grow from there. A few months later, Youtube user TaranikiFarm copied and uploaded the 1980s documentary, The Power of Compost, focusing on Jean Pain's method, made back in the early 80s as well. Jean Pain drew 18 months of energy from his large compost pile. Heating and gas, 100% of his energy needs, including his truck and machines!

This fact sheet says that HDPE will burn at 343degC, releasing toxic gases. More searching tells me at least one of those gases is hydrochloric acid gas. But so far nothing to say it is released at the relatively low temps of composting heat (60degC) and water at that temp. Also, I've found noting about other toxic gases that come from HDPE when burning.

I think I might need to take a with a lonely chemist from the university.

Jude and Kerry, there is a smell coming through - one of ammonia... No one else reports a smell, so something is wrong with my system. It could be 3 things: 1. I mixed horse poo in - no one else did this as far as I know. It might be that it has made the pile too hot, and the pipe is breathing as a result!2. The pipe I bought is low grade. It is green stripe HDPE rated to hold 650Kpa of pressure. There is a more expensive pipe called blue stripe, which can hold more pressure. I think the only difference is thickness.3. The pipe has burst and melted, letting in compost tea. This is unlikely, and I have monitored the meter, no water has passed through in 12 hours.

So, I think - don't use horse poo, and buy blue stripe. The only reason I mixed poo in was to get a good humus at the end. It has been more hassle than it's worth. Flies everywhere, and possibly too hot. If HDPE 'breathes' when it is hot, then use eucalyptus woodchip, and your smell will be a nice smell. Hopefully ours will stop smelling as the reaction calms down and cools off a little. It is VERY hot now. As it is now, the smell is not too bad, but it is noticeable. The fact that no one else reports the problem tells me it is just my system...

A 4th consideration is that I have connected it to mains pressure, reduced to 500Kpa. 500Kpa heated may be compromising the pipe also... not sure how to work out the pressure, I think it is Volume x Temp... but again, no leaks indicated on the meter...?

talked with water monitors in the Ecology Faculty of UC. They couldn't think of anything that would be generating the smell and thought it impossible that the pipe is breathing. They suggested flushing the system as it might simply be something in the new pipe that needs cleaning. They also suggested that I might have accidentally scooped horse poo into the pipe and it was stuck in the restricting end, generating the smell.. Finally, if I thought it was the HDPE giving off an acid, I should test it with bicarbonated soda. If it is acid, there will be a gas reaction when the bicarb is added. I will try thins, although since rebuilding the pile, I've notice the smell has dropped considerably.. might just be new pipe smell... more videos getting added to the playlist as I go...

marc torradesi am a french gardener,we use to keep outside geranium under cold frame and we use a similar method with cow manure. the cold frame were sitting on trench in the ground ( 1,30meter wide, 0.60meter deep, 5meter long). the external temperature in winter are much colder than provence, in february it could -20Centigrade for 3 weeks, and this sytem would provide enough heat to the plants to survive with no frost damage. we use thick cow manure because the horse manure burn to fast, we call in french the "coup de feu" when the highest heat would start, with the horse manure this could reach easily 90degree centigrade even higher but with cow one only 70 degree but it would give it for a longer time. i never try with wood. keep the good work.i would interested when you make methane. good luck with it

Hi Marc, many thanks for that advice. I will remix again but this time try and find cow manure. Horse is easier because there is a race track nearby.. cow might be a little harder, I'll look for a milking shed. The woodchips added makes it a little harder to get the heat. I think I need to mix it 2 parts manure, to 1 part woodchips. Theory being the woodchips will help keep it hotter for longer. Will attempt methane then too. Have started a Rocket Stove Thermal Fire project too

Update on the compost hot water system. A comment on Youtube tells me to use B Plex pipe. I think more likely, I will use about 10metres of coper pipe connected to an insulated storage tank. Am getting ready to try this in winter.

I`m nearly completed my own Jean Pain heat compost system. I placed an old uninsulated 40 gal tank in the middle of my 15 ft wide pile, and is now at 5 ft high. I figure I still need another 5 ft on top to finish it. I`m getting luke warm water out of it right now. I`m using 3/4, 75 psi poly pipe at the intake and 100 psi at the outake. I did not use a coil system and I`m not sure if that will be a mistake. My intension is to insulate the pile using straw bales straight to the top. I`ve insulated the intake and outake using standard foam pipe insulation and will also box it in with straw bales. I will also put rat traps just in case it attracks them. I`m not at the methane level yet. Our zone is 5b. Sorry I don`t know what URL means.